Micro- and nano-scale additive manufacturing methods in metals, plastics, and ceramics have many applications in the aerospace, medical device, and electronics industries. For example, the fabrication of additively-manufactured parts with micron-scale resolutions makes possible the production of cellular materials with controlled microstructures. Such materials can exhibit very high strength-to-weight ratios, which is critical for a number of applications in the aerospace industry. Similarly, the medical industry could benefit from the additive manufacturing of metal parts with controlled microstructures, since this process could be used to fabricate custom implants with enhanced surface structures to either promote or prevent the adhesion of cells to the implant in specific areas. Similarly, controlled microstructures may be used in a number of microelectronic packaging applications.
Selective laser micro-sintering (or micro-selective laser sintering “μ-SLS” or “micro-SLS”) is an additive manufacturing technology that uses a high power laser to manufacture a three-dimensional component (e.g., a part), under condition of vacuum or reduced shield gas pressure, in a layer-by-layer fashion from a powder (e.g., plastic, metal, polymer, ceramic, composite materials, etc.). That is, powders are spread onto a powder bed and a laser beam is scanned across the powder bed to sinter together the powders at the scanned locations; a new layer of powder is then spread onto the bed over the sintered layer and the process is repeated to build a three-dimensional part.
One class of commercially available metal additive manufacturing tools has feature-size resolutions up to 100 μm (micrometers). In many applications, e.g., microelectronic packaging, among others, these feature-size resolutions are too coarse to precisely control microstructures of parts desired to be produced. Existing research-based systems for metal additive manufacturing may fabricate finer resolutions features, but have low through-put that are not yet viable for commercial use.
To manufacture parts with smaller feature-sizes, manufacturing via smaller particles, at the nanoscale, such as with nanoparticles are employed. Because of their size, agglomeration of nanoparticles (e.g., nanoparticle powder) can form, which can lead to the formation of defects in the final produced part. In addition to agglomeration, at the sub-micron (μm) level, the interaction between nanoparticles (e.g., nanoparticle powder) under high power laser heating raises additional near-field thermal issues such as thermal diffusivity, effective absorptivity, and extinction coefficients as compared to larger scales processes.
Flexible electronics may include the integration of a diverse set of high quality, silicon-based electrical components including CMOS integrated circuit (IC) chips (i.e. microprocessors, memory, etc.), radio frequency (RF) devices, power management subsystems, passive components, biochips, sensors, actuators, and microelectromechanical systems (MEMS) onto a single flexible substrate. The integration of such complex devices onto flexible substrates of requires high input/output (I/O) pin counts of these devices that can carry the high quality analog signals required by many of these components.
Currently there are several methods available for the direct write of microscale features. One type of methods (e.g., Vat photo-polymerization) generally operates only using polymeric materials. Another type of method (e.g., material jetting) is commonly used in the fabrication of 2D printed electronic structures.
Therefore, what are needed are devices, systems and methods that overcome challenges in the present art, some of which are described above.